US6369293B1ExpiredUtility

Absorbent composition including an uncrosslinked polymer

63
Assignee: KIMBERLY CLARK COPriority: Nov 4, 1998Filed: Sep 14, 1999Granted: Apr 9, 2002
Est. expiryNov 4, 2018(expired)· nominal 20-yr term from priority
Inventors:William G. ReevesWilliam Galey RobertsonMary Jeanne DupuisEric Scott KepnerThomas Patrick JorgensonGerald Lee Richmond
C08L 71/02A61F 2013/530751A61F 2013/530481C08G 65/30A61L 15/60A61F 2013/530708Y10T428/249958Y10T428/249953
63
PatentIndex Score
23
Cited by
17
References
36
Claims

Abstract

An absorbent composition comprising an uncrosslinked, high molecular weight polymer, wherein the uncrosslinked, high molecular weight polymer is treated by a means to effectively insolubilize the uncrosslinked, relatively high molecular weight polymer such that the absorbent composition exhibits desirable absorbent properties. In particular, the absorbent composition has the ability to absorb a large quantity of liquid. The absorbent composition is useful in disposable absorbent products, such as those disposable absorbent products that are used to absorb bodily liquids. Suitable polymers include polyethylene oxide, poly(acrylic acid), poly(vinyl alcohol), and poly(vinyl pyrrolidone) wherein the polymer has a weight average molecular weight that is greater than about 1,000,000.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
       1. An absorbent composition comprising an uncrosslinked polymer, wherein the uncrosslinked polymer has a weight average molecular weight greater than about 1,000,000 and wherein the absorbent composition exhibits a Free Swell value that is at least about 15 grams of water per gram of absorbent composition and a Centrifuge Retention Capacity value that is at least about 8 grams of water per gram of absorbent composition, wherein the time period used to determine both the Free Swell value and the Centrifuge Retention Capacity value is about 19 hours. 
     
     
       2. The absorbent composition of  claim 1  wherein the uncrosslinked polymer is selected from the group consisting of polyethylene oxide, poly(acrylic acid), poly(vinyl alcohol), poly(vinyl pyrrolidone), copolymers of such polymers, and mixtures of such polymers. 
     
     
       3. The absorbent composition of  claim 2  wherein the uncrosslinked polymer is polyethylene oxide. 
     
     
       4. The absorbent composition of  claim 1  wherein the uncrosslinked polymer has a weight average molecular weight greater than about 1,500,000. 
     
     
       5. The absorbent composition of  claim 4  wherein the uncrosslinked polymer has a weight average molecular weight greater than about 2,000,000. 
     
     
       6. The absorbent composition of  claim 5  wherein the uncrosslinked polymer has a weight average molecular weight greater than about 3,000,000. 
     
     
       7. The absorbent composition of  claim 1  wherein the absorbent composition exhibits a Free Swell value that is at least about 20 grams of water per gram of absorbent composition. 
     
     
       8. The absorbent composition of  claim 1  wherein the absorbent composition exhibits a Centrifuge Retention Capacity value that is at least about 10 grams of water per gram of absorbent composition. 
     
     
       9. An absorbent composition comprising an uncrosslinked polymer, wherein the uncrosslinked polymer has a weight average molecular weight greater than about 1,000,000 and wherein the absorbent composition exhibits a Free Swell value that is at least about 15 grams of a 0.9 weight percent solution of sodium chloride in distilled water per gram of absorbent composition and a Centrifuge Retention Capacity value that is at least about 8 grams of a 0.9 weight percent solution of sodium chloride in distilled water per gram of absorbent composition, wherein the time period used to determine both the Free Swell value and the Centrifuge Retention Capacity value is about 19 hours. 
     
     
       10. The absorbent composition of  claim 9  wherein the uncrosslinked polymer is selected from the group consisting of polyethylene oxide, poly(acrylic acid), poly(vinyl alcohol), poly(vinyl pyrrolidone), copolymers of such polymers, and mixtures of such polymers. 
     
     
       11. The absorbent composition of  claim 10  wherein the uncrosslinked polymer is polyethylene oxide. 
     
     
       12. The absorbent composition of  claim 9  wherein the uncrosslinked polymer has a weight average molecular weight greater than about 1,500,000. 
     
     
       13. The absorbent composition of  claim 12  wherein the uncrosslinked polymer has a weight average molecular weight greater than about 2,000,000. 
     
     
       14. The absorbent composition of  claim 13  wherein the uncrosslinked polymer has a weight average molecular weight greater than about 3,000,000. 
     
     
       15. The absorbent composition of  claim 9  wherein the absorbent composition exhibits a Free Swell value that is at least about 20 grams of a 0.9 weight percent solution of sodium chloride in distilled water per gram of absorbent composition. 
     
     
       16. The absorbent composition of  claim 9  wherein the absorbent composition exhibits a Centrifuge Retention Capacity value that is at least about 10 grams of a 0.9 weight percent solution of sodium chloride in distilled water per gram of absorbent composition. 
     
     
       17. A process for preparing an absorbent composition comprising an uncrosslinked polymer, the process comprising: 
       a. preparing a mixture of a solvent soluble, uncrosslinked polymer that has a molecular weight greater than about 1,000,000 and a solvent in which the uncrosslinked polymer is soluble, wherein the soluble, uncrosslinked polymer dissolves into the solvent; and  
       b. recovering the uncrosslinked polymer from the mixture,  
       wherein the absorbent composition exhibits a Free Swell value that is at least about 15 grams of water per gram of absorbent composition and a Centrifuge Retention Capacity value that is at least about 8 grams of water per gram of absorbent composition, wherein the time period used to determine both the Free Swell value and the Centrifuge Retention Capacity value is about 19 hours. 
     
     
       18. The process of  claim 17  wherein the process further comprises first preparing a mixture of the solvent soluble, uncrosslinked polymer and a non-solvent. 
     
     
       19. The process of  claim 17  wherein the solvent comprises water, acetone, methyl ethyl ketone, methanol, ethanol, dimethylsulfoxide, or hexamethylphosphoramide. 
     
     
       20. The process of  claim 19  wherein the solvent consists essentially of water. 
     
     
       21. The process of  claim 18  wherein the non-solvent comprises methanol. 
     
     
       22. The process of  claim 17  wherein the uncrosslinked polymer is recovered from the mixture by a method selected from the group consisting of evaporative drying, freeze drying, precipitation, and critical point drying. 
     
     
       23. A process for preparing an absorbent composition comprising an uncrosslinked polymer, the process comprising: 
       a. preparing a mixture of a solvent soluble, uncrosslinked polymer that has a molecular weight greater than about 1,000,000 and a solvent in which the uncrosslinked polymer is soluble, wherein the soluble, uncrosslinked polymer dissolves into the solvent; and  
       b. recovering the uncrosslinked polymer from the mixture,  
       wherein the absorbent composition exhibits a Free Swell value that is at least about 15 grams of a 0.9 weight percent solution of sodium chloride in distilled water per gram of absorbent composition and a Centrifuge Retention Capacity value that is at least about 8 grams of a 0.9 weight percent solution of sodium chloride in distilled water per gram of absorbent composition, wherein the time period used to determine both the Free Swell value and the Centrifuge Retention Capacity value is about 19 hours. 
     
     
       24. The process of  claim 23  wherein the process further comprises first preparing a mixture of the solvent soluble, uncrosslinked polymer and a non-solvent. 
     
     
       25. The process of  claim 23  wherein the solvent comprises water, acetone, methyl ethyl ketone, methanol, ethanol, dimethylsulfoxide, or hexamethylphosphoramide. 
     
     
       26. The process of  claim 25  wherein the solvent consists essentially of water. 
     
     
       27. The process of  claim 24  wherein the non-solvent comprises methanol. 
     
     
       28. The process of  claim 23  wherein the uncrosslinked polymer is recovered from the mixture by a method selected from the group consisting of evaporative drying, freeze drying, precipitation, and critical point drying. 
     
     
       29. A process for preparing an absorbent composition comprising a solvent insoluble uncrosslinked polymer, the process comprising treating a solvent soluble, uncrosslinked polymer by means of heat and pressure effective to insolublize the uncrosslinked polymer, wherein the absorbent composition exhibits a Free Swell value that is at least about 15 grams of water per gram of absorbent composition and a Centrifuge Retention Capacity value that is at least about 8 grams of water per gram of absorbent composition, wherein the time period used to determine both the Free Swell value and the Centrifuge Retention Capacity value is about 19 hours. 
     
     
       30. The process of  claim 29  wherein the solvent soluble, uncrosslinked polymer is treated at a temperature between about 10° C. to about 250° C. 
     
     
       31. The process of  claim 29  wherein the solvent soluble, uncrosslinked polymer is treated at a pressure between about 100 pounds per square inch to about 10,000 pounds per square inch. 
     
     
       32. A process for preparing an absorbent composition comprising a solvent insoluble uncrosslinked polymer, the process comprising treating a solvent soluble, uncrosslinked polymer by means of heat and pressure effective to insolublize the uncrosslinked polymer, wherein the absorbent composition exhibits a Free Swell value that is at least about 15 grams of a 0.9 weight percent solution of sodium chloride in distilled water per gram of absorbent composition and a Centrifuge Retention Capacity value that is at least about 8 grams of a 0.9 weight percent solution of sodium chloride in distilled water per gram of absorbent composition, wherein the time period used to determine both the Free Swell value and the Centrifuge Retention Capacity value is about 19 hours. 
     
     
       33. The process of  claim 32  wherein the solvent soluble, uncrosslinked polymer is treated at a temperature between about 10° C. to about 250° C. 
     
     
       34. The process of  claim 32  wherein the solvent soluble, uncrosslinked polymer is treated at a pressure between about 100 pounds per square inch to about 10,000 pounds per square inch. 
     
     
       35. A process for preparing an absorbent composition comprising a solvent insoluble uncrosslinked polymer, the process comprising complexing a solvent soluble, uncrosslinked polymer with a complexing agent, wherein the absorbent composition exhibits a Free Swell value that is at least about 15 grams of water per gram of absorbent composition and a Centrifuge Retention Capacity value that is at least about 8 grams of water per gram of absorbent composition, wherein the time period used to determine both the Free Swell value and the Centrifuge Retention Capacity value is about 19 hours. 
     
     
       36. The process of  claim 35  wherein the uncrosslinked polymer is polyethylene oxide and the complexing agent is poly(acrylic acid).

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